I made this recently. It's not perfect as it comes from a multitude of sources stitched together over many different years with different measurement procedures, and I had to adjust some numbers to match sources, but I think overall it is a pretty accurate reflection of reality. I started with the most recent census data for different countries and found other sources to fill in the gaps.

Is Switzerland really predominatly Catholic?I thought Calvinists formed the majority.

Well some parts of Switzerland were historically Protestant and others were Catholic. However with increasing secularization, Protestants tended to leave the church more than Catholics. The case is the same with other countries such as the Netherlands.

Is Switzerland really predominatly Catholic?I thought Calvinists formed the majority.

Well some parts of Switzerland were historically Protestant and others were Catholic. However with increasing secularization, Protestants tended to leave the church more than Catholics. The case is the same with other countries such as the Netherlands.

Yes, especially when it comes to nominal affiliation. Protestants have a habit of either lovign or hating the church of their birth.

Some of the patterns are quite interesting such as the Protestant belt in Central America or the more Buddhist vs. more secular areas of Japan.

But are the non-yellow areas in Japan light browns or light greys? If the latter, realisticidealist, how on earth did your sources distinguish between Buddhist and Shinto practice in Japan to that degree?

I thought the UK was plurality Catholic now? (Speaking of the UK, why did you only divide them up by the Home Countries- I would have at least used the regional level)

England is nowhere near being plurality Catholic (not that the Census records this information) The most reliable indicator of denominationalism is the British Social Attitudes Survey which in 2013 suggested Britain as a whole was plurality Non-Religious (48%) Anglicans account for 20% and Catholics for 9%. Certainly at current trends Anglican might end up at 15% or so with Catholicism at around 10% (adherence to Catholicism, suggesting a cultural rather than religious association has flatlined since the survey began in 1983) with the Non-Religious breaking 55-60% (Nones are already at 60% amongst the under 30ís and about 42% in the formal Census) but England will not be plurality Catholic any time soon.

The trend towards Catholicism is partly due to the reasons other posters have mentioned already and because of immigration; the high number of Italian, Spanish and Portuguese immigrants, for example, has boosted Catholic strength in Switzerland.

Some of the patterns are quite interesting such as the Protestant belt in Central America or the more Buddhist vs. more secular areas of Japan.

But are the non-yellow areas in Japan light browns or light greys? If the latter, realisticidealist, how on earth did your sources distinguish between Buddhist and Shinto practice in Japan to that degree?

I used data from Japan's Statistics Bureau. It appears they counted some people as practicing both Shinto and Buddhism. I'm not sure what their methodology beyond that is, though.

Just a few points on my home turf. If you are calculating 'No Religion' for Scotland then census guidance suggests that should include those who not only actively declare 'No Religion' on their Census box, but also don't fill it in ('Religion not stated') as faith is a declaration yadda yadda. That boosts the grey somewhat.